'\" t
.TH "SD_BUS_SET_SERVER" "3" "" "systemd 256.7" "sd_bus_set_server"
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.SH "NAME"
sd_bus_set_server, sd_bus_is_server, sd_bus_get_bus_id, sd_bus_set_bus_client, sd_bus_is_bus_client, sd_bus_set_monitor, sd_bus_is_monitor \- Configure connection mode for a bus object
.SH "SYNOPSIS"
.sp
.ft B
.nf
#include <systemd/sd\-bus\&.h>
.fi
.ft
.HP \w'int\ sd_bus_set_server('u
.BI "int sd_bus_set_server(sd_bus\ *" "bus" ", int\ " "b" ", sd_id128_t\ " "id" ");"
.HP \w'int\ sd_bus_is_server('u
.BI "int sd_bus_is_server(sd_bus\ *" "bus" ");"
.HP \w'int\ sd_bus_get_bus_id('u
.BI "int sd_bus_get_bus_id(sd_bus\ *" "bus" ", sd_id128_t\ *" "id" ");"
.HP \w'int\ sd_bus_set_bus_client('u
.BI "int sd_bus_set_bus_client(sd_bus\ *" "bus" ", int\ " "b" ");"
.HP \w'int\ sd_bus_is_bus_client('u
.BI "int sd_bus_is_bus_client(sd_bus\ *" "bus" ");"
.HP \w'int\ sd_bus_set_monitor('u
.BI "int sd_bus_set_monitor(sd_bus\ *" "bus" ", int\ " "b" ");"
.HP \w'int\ sd_bus_is_monitor('u
.BI "int sd_bus_is_monitor(sd_bus\ *" "bus" ");"
.SH "DESCRIPTION"
.PP
\fBsd_bus_set_server()\fR
configures the bus object as a server for direct D\-Bus connections\&.
\fIb\fR
enables/disables the server mode\&. If zero, the server mode is disabled\&. Otherwise, the server mode is enabled\&. Configuring a bus object as a server is required to allow establishing direct connections between two peers without going via the D\-Bus daemon\&.
\fIid\fR
must contain a 128\-bit integer id for the server\&. If clients add a guid field to their D\-Bus address string, the server id must match this guid or the D\-Bus authentication handshake will fail\&. If no specific id is defined for the server,
\fBsd_id128_randomize\fR(3)
can be used to generate a random id instead\&.
.PP
\fBsd_bus_is_server()\fR
returns whether the server mode is enabled for the given bus object\&.
.PP
\fBsd_bus_get_bus_id()\fR
stores the D\-Bus server id configured using
\fBsd_bus_set_server()\fR
(for server bus objects) or received during D\-Bus authentication (for client bus objects) in
\fIid\fR\&.
.PP
\fBsd_bus_set_bus_client()\fR
configures the bus object as a D\-Bus daemon client\&.
\fIb\fR
enables/disables the client mode\&. If zero, the client mode is disabled and the bus object should connect directly to a D\-Bus server\&. Otherwise, the client mode is enabled and the bus object should connect to a D\-Bus daemon\&. When connecting to an existing bus using any of the functions in the
\fBsd_bus_open\fR(3)
family of functions or any of the functions in the
\fBsd_bus_default\fR(3)
family of functions, the bus object is automatically configured as a bus client\&. However, when connecting to a D\-Bus daemon by calling
\fBsd_bus_set_address\fR(3)
followed by
\fBsd_bus_start\fR(3), the bus object should be manually configured as a bus client using
\fBsd_bus_set_bus_client()\fR\&. By default, a bus object is not configured as a D\-Bus daemon client\&.
.PP
\fBsd_bus_is_bus_client()\fR
returns whether the client mode is enabled/disabled for the given bus object\&.
.PP
\fBsd_bus_set_monitor()\fR
configures the bus object as a D\-Bus monitor object\&.
\fIb\fR
enables/disables the monitor mode\&. If zero, the monitor mode is disabled\&. If non\-zero, the monitor mode is enabled\&. When the monitor mode is enabled, no messages may be sent via the bus object and it may not expose any objects on the bus\&. To start monitoring messages, call the
\fBorg\&.freedesktop\&.DBus\&.Monitoring\&.BecomeMonitor\fR
method of the D\-Bus daemon and pass a list of matches indicating which messages to intercept\&. See
\m[blue]\fBThe D\-Bus specification\fR\m[]\&\s-2\u[1]\d\s+2
for more information\&.
.PP
\fBsd_bus_is_monitor()\fR
returns whether the monitor mode is enabled/disabled for the given bus object\&.
.SH "RETURN VALUE"
.PP
On success,
\fBsd_bus_set_server()\fR,
\fBsd_bus_get_bus_id()\fR,
\fBsd_bus_set_bus_client()\fR
and
\fBsd_bus_set_monitor()\fR
return a non\-negative integer\&. On failure, they return a negative errno\-style error code\&.
.PP
\fBsd_bus_is_server()\fR,
\fBsd_bus_is_bus_client()\fR
and
\fBsd_bus_is_monitor()\fR
return a positive integer when the server or client mode is enabled, respectively\&. Otherwise, they return zero\&.
.SS "Errors"
.PP
Returned errors may indicate the following problems:
.PP
\fB\-ECHILD\fR
.RS 4
The bus connection has been created in a different process, library or module instance\&.
.sp
Added in version 246\&.
.RE
.PP
\fB\-EPERM\fR
.RS 4
The bus connection has already been started\&.
.sp
Added in version 246\&.
.RE
.PP
\fB\-ENOPKG\fR
.RS 4
The bus cannot be resolved\&.
.sp
Added in version 246\&.
.RE
.PP
\fB\-EINVAL\fR
.RS 4
A required parameter was
\fBNULL\fR
or
\fIb\fR
was zero and
\fIid\fR
did not equal
\fBSD_ID128_NULL\fR\&.
.sp
Added in version 246\&.
.RE
.PP
\fB\-ENOTCONN\fR
.RS 4
The bus is not connected\&.
.sp
Added in version 246\&.
.RE
.SH "NOTES"
.PP
Functions described here are available as a shared library, which can be compiled against and linked to with the
\fBlibsystemd\fR\ \&\fBpkg-config\fR(1)
file\&.
.PP
The code described here uses
\fBgetenv\fR(3), which is declared to be not multi\-thread\-safe\&. This means that the code calling the functions described here must not call
\fBsetenv\fR(3)
from a parallel thread\&. It is recommended to only do calls to
\fBsetenv()\fR
from an early phase of the program when no other threads have been started\&.
.SH "HISTORY"
.PP
\fBsd_bus_set_server()\fR,
\fBsd_bus_is_server()\fR,
\fBsd_bus_get_bus_id()\fR,
\fBsd_bus_set_bus_client()\fR,
\fBsd_bus_is_bus_client()\fR,
\fBsd_bus_set_monitor()\fR, and
\fBsd_bus_is_monitor()\fR
were added in version 246\&.
.SH "SEE ALSO"
.PP
\fBsystemd\fR(1), \fBsd-bus\fR(3)
.SH "NOTES"
.IP " 1." 4
The D-Bus specification
.RS 4
\%https://dbus.freedesktop.org/doc/dbus-specification.html#bus-messages-become-monitor
.RE
